Add triple click to select all in TextBox

[Kuuuube]

Small qol feature. I triple click on textboxes a lot and it's a bit jarring to be unable to do this in osu.

If desirable, I could implement this as a whole different event like DoubleClickEvent but I can't think of a use case outside of TextBox so I'm not sure that's worth it. Tried to follow the existing project structure as closely as I could.

Closes #4974

[Joehuu]

If desirable, I could implement this as a whole different event like DoubleClickEvent but I can't think of a use case outside of TextBox so I'm not sure that's worth it. Tried to follow the existing project structure as closely as I could.

The past attempt in #4975 did that and wasn't accepted.

This also closes #4974 (can't edit OP).

[Kuuuube]

Issue linked in OP. Thanks for pointing that out.

[bdach]

Needs tests. Not willing to review until there's tests.

[Kuuuube]

Added tests for triple click selecting all and a triple click that is too slow to select.

[bdach]

Not sure how to feel about the following behaviour:

Screen.Recording.2025-10-07.at.08.52.14.mov

For reference macOS stops changing the selection after the third click and I think that'd be a better behaviour here too.

[Kuuuube]

For reference macOS stops changing the selection after the third click and I think that'd be a better behaviour here too.

If you want it to work that way here, I won't fight you over it. I have no strong opinions here. But consider that almost everything else does allow the selection to change (testing of various programs on Windows and Linux):

untitled.mp4

The most common behavior appears to be select all -> deselect though select all -> select word is not uncommon either and can be seen in Qt (the Kate example) and Windows system ui.

(also small behavior change with 95b39dc for dragging, everything I tested this with did not allow text selection to change when dragging while a triple click is ongoing so that's added now)

[bdach]

(also small behavior change with 95b39dc for dragging, everything I tested this with did not allow text selection to change when dragging while a triple click is ongoing so that's added now)

Please add a test case for this.

[Kuuuube]

Test added.

[bdach]

no real remaining concerns from me I guess

@peppy maybe check that you're OK with the UX side of this